Stromata superficial, effused-pulvinate, up to 8 cm long × 0.3–0.2 cm wide; with inconspicuous to conspicuous perithecial mounds, surface Red (2) to Brick (59); Scarlet (5) to Orange (7) granules beneath the surface and between the perithecia, with Orange (7) to Scarlet (5) KOH-extractable pigments. Perithecia spherical to obovoid, 0.2–0.5 high × 0.15–0.45 mm wide. Ostioles umbilicate, inconspicuous. Asci 8-spored, cylindrical, with amyloid, discoid apical apparatus, 0.5–1 µm high × 1.5–2.5 µm wide, stipe up to 180 µm long and spore-bearing portion 40–80 × 6.5–10 µm. Ascospores smooth, unicellular, brown to dark brown, ellipsoid, inequilateral with narrowly rounded ends, 9–12 (–13) × 4–6 µm, with straight germ slit spore-length on convex side; perispore dehiscent in 10% KOH; epispore smooth.

Colonies on OA covering a 9 cm Petri dish in 3 wk, at first white, becoming Smoke Grey (105), felty, azonate with diffuse margins; finally becoming Pale Luteous (11) to Straw (46). Asexual morph not produced in culture.

Rubiginosin A and an unknown compound of the mitorubrin / rubiginosin azaphilone family prevalent; cultures produce phomopsidin and unidentified compounds on barley-malt agar.

Iran, Guilan Province, Siahkal County, Deilaman forest, 36°57'25"N, 49°51'54"E, 1100 m elev., on fallen branch of Quercus castaneifolia, 6 Oct 2017 (GUM 1586; culture MUCL 57727); Guilan Province, Shaft County, 36°59'08"N, 49°18'43"E, 594 m elev., on fallen trunk of Pterocarya fraxinifolia, 15 Sep 2015 (GUM 1583); Guilan Province, Langaroud County, Liseroud forest, 37°7'44"N, 50°8'41"E, 28 m elev., on fallen branch of Quercus castaneifolia, 10 Sep 2016 (GUM 1584); Guilan Province, Talesh County, Gisoum forest, 37°37'30"N, 48°58'15"E, 477 m elev., on fallen branch of Populus sp., 20 Oct 2016 (GUM 1585). All specimens collected by M.J. Pourmoghaddam.

H. rubiginosumsensu stricto is a very common fungus in the temperate Northern hemisphere (Stadler et al. 2008) and may occur in subtropical areas, such as Florida, USA (Ju and Rogers 1996). Most of the characters of the Iranian specimens are in accordance with previous descriptions (Stadler et al. 2004), aside from insignificant variations in the size of ascospores.